The surface of the line is small pee-size shingle gravel ontop of a larger aggregate. Generally the path is worn to almost powder on the outsides of the path, where cyclist ride up and down. The centre has more of a build up of pee-shingle gravel. The path is about 8 feet wide and popular with walkers and cyclists alike. Cyclists are asked to slow down and sound a bell when passing pedestrians, including errant children and loose dogs. The strawberry line is passable on a road bike with little trouble, obviously the surface is flat, with little pot holes. I was able to cruise at 17mph on 23mm tires no problem. If your tires are susceptible to punctures you may wish to think twice and there is a perfectly good alternative route on Nye Road which turns into Puxton Lane. I would say the path is passable in all weathers including wet conditions, although clay mud will get flung up onto your bike, in anything but dry conditions.
For more information check out the website or just Get on Your Bike.